Both players were substituted in Tuesday night's draw with Brighton & Hove Albion, Evans coming off with a dead leg, whilst midfield partner Williamson received a kick above his knee.
Neither player has trained since the midweek match, but the manager is optimistic that both will be fit to feature on Saturday, but Jason Lowe misses out once more with a troublesome ankle injury.
"Corry has progressed nicely and we hope he trains tomorrow, it isn't as bad as first feared," said the Rovers boss.
"It is the same with Lee Williamson, so those two have done really well since Tuesday.
"Jason Lowe is still a little but short at the moment but we are hoping that after this weekend he should be close.
"It is just a bit annoying, for the lad especially, his legs and his energy and enthusiasm for the game, we certainly need that for the run-in."
Rudy Gestede was only a late substitute against Brighton, with Bowyer believing that resting him from the start has allowed his groin injury to settle down.
Bowyer added: "Rudy is fine, I think it was the right thing to do, to look after him. He should now make sure that he is available for every game."
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